The present disclosure relates generally to the field of connection devices for electrical shielded cables and the like. The disclosure has particular utility for use of a cable clamp or backshell with electromagnetic emission “EME”/high intensity radio frequency “HIRF” connector assemblies, and will be discussed in connection with such utility, although other utilities are contemplated.
The disclosed subject matter relates, generally, to improvements in cable termination and grounding assemblies for improved performance in EME/HIRF utilizations, including through enabling more repeatable, reliable and reworkable assembly/installation and better shield grounding. There are several important considerations in the designing of such an assembly. First, the cable clamp, also called a “backshell”, can be used as an EME/HIRF grounding device providing high surface transfer impedance shielding, noise immunity and susceptibility, at all frequency ranges and as a strain relief device providing mechanical support or both in the assembly of electrical shielded cable. Second, the performance attributes of a cable clamp such as its shielding (conductivity) properties, coupling mechanism, corrosion resistivity and usage application should preferably be maximized at least to some extent while the related assembly tools and operator skill/learning attributes should be minimized at least to some extent. Another desirable feature would be the provision of an environmental sealing capability which would prevent ingress of contaminants, fluid or grime or otherwise, onto the electrical connector. In particular, cable clamps installed in applications such as aircraft may be subject to fluids such as fuel, cleaning fluid, lubricating fluid, deicing fluid, hydraulic fluid, water and other substances not desired to contact electrical connections.
While prior art cable clamp mechanisms have been industry accepted, several deficiencies and disadvantages exist. For example, ground shield termination using lugs and a commonly accepted method called “banding” to terminate electrical cable individual and overall shields requires laborious, error-prone, non-reusable assembly. Another example is the plating finish used to protect the “backshell” from corrosion inducing contaminants such as hydraulic, aviation and de-icing fluids, and other contaminants while meeting electrical shielding and conductivity requirements. Also, the cost associated with customized cable clamps, to be either straight or angular due to installation usage, can be significant.
Existing solutions can employ devices and assembly processes and methodology that are in need of improvement. Surface transfer impedance (“STI”), resistance (at low frequency) and mutual inductance (at high frequency) have proven to be a function of the cable shield and backshell assembly process at installation and the mating of the backshell and connector during installation, including variability in the shield coverage of the backshell. Existing solutions are also less than cost effective and can be improved in terms of weight considerations.
Various backshell cable termination and grounding designs are known in the art for use in the same or similar applications as evidenced by U.S. Pat. Nos. 6,846,201, 6,406,329, and 6,116,955, owned by applicants assignee, the disclosures of which are hereby incorporated by reference.
Despite these developments, there remains a need for a cable backshell assembly that can facilitate the connection and performance of the electrical cable to a connector, while eliminating the prior art individual cable shielding termination and shielding tape used to attempt to enhance electromagnetic emission (“EME”) and/or high intensity radio frequency (“HIRF”) properties. Also needed is improvement in environmental protection of the design.
Accordingly, there is a need in the art for an improved cable termination and grounding mechanism that may be efficiently and cost-effectively used and/or produced and/or installed.